Unprofitable neighborhood - rats, mice, mouse, earther, gopters, "pussy", chipmunks, bear.

Different types of rodents bring us many losses, troubles, and sometimes diseases. This is an undesirable neighborhood from which we strive to get rid of different ways - We spend money on the purchase of poisons, traps, traps, chemicals, biological products, etc. But often our efforts are in vain.

Agree when you care for plants, see how they grow, flourish ... And "they" come, what to do?

There are many ways to combat rodents. In this article we will talk about more new and safe, and in a monetary meaning and economical method of combating our "friends" smaller.

An important discovery was the discovery of the dislike of rodents to the sounds of high frequency (ultrasound), which do not hear an ordinary person and low-frequency sounds propagating in the ground. Electronic devices Emitting frequency data, safe for people, pets and birds, underground insects do not cause interference in the work of the body and radio equipment.

I want to present you a number of concept schemes for scaring rodents. (1 - underground rodents, 2 - rats, mice, etc.)

1. Underground rodents (moles, earthying, bear)
As you know, they use their aggravated hearing to capture the soil vibrations. The vibration of the soil warns rodents about the danger and forces them to flee. We can use this fact.

It is enough to create sound vibration in the soil with a frequency of 100 to 400 Hz. You can use the speaker from the old low-power receiver as the emitter. The emitter is buried to a depth of 30 - 50 cm in the ground.

Let's start with the simplest devices. For their manufacture, the most common details are used.

Option number 1
You can apply a sound multivibrator to P-N-P or N-P-N transistors. With a supply voltage of 4.5 - 9 V, its power is sufficient to propagate the signal by 300 - 1000 m2. The disadvantage of this design is constant work. Theoretically, the signal should come in periods and you will have to turn on and turn off the multivibrator.

When using listed parts, the signal frequency is about 200 Hz. Speaker B1 - 0.25 W or 0.5 W.

Fig. one.
R1, R4 - 1 com; R2, R3 - 39 com; R5 - 510 Ohms; C1, C2, C3 - 0.1 μF; V1, V2 - MP 26 or MP42; V3 - GT 402, GT403.

Fig. 2.
R1, R4 - 1 com; R2, R3 - 39 com; R5 - 1kom; C1, C2, C3 - 0.1 μF; V1, V2 - KT315; V3 - KT815

Option number 2.
As I noted above, the signal must be emitted periodically, so we emulate the movement of the earth's layers as before the earthquake. This can be achieved using two multivibrators, one of which radiates the signal you need, the second manages the operation of the first multivibrator. As a result, we will hear "Bip-Pause-Bip Pause, etc.". The schematic diagram is shown in Fig.3.


Fig. 3.
Details: RP - 100kom; R1, R4, R6, R9 - 1 com; R2, R3 - 47 kΩ; R7, R8 - 27 com; R5, R10 - 510 Ohms; C1, C2, - 500 μF; C3, C4 - 0.22 μF; C5 - 0.1 μF; V1, V2, V4, V5 - MP 26 or MP42; V3, V6 - CT 814, CT 816; VD1, VD2 - al 307; B1 - 0.5 or 1 W resistance of 8 ohm.

Consider how the electronic "filling" of the repeller works in Fig.3. The basis of the device is multivibrators. One of them on transistors V4 and V5 generate oscillations with a frequency of about 200 Hz. The V6 transistor - enhances the power of these oscillations. As can be seen from the multivibrator circuit on the transistors V4, V5, V6 are the load of the right shoulder of the multivibrator collected on the transistors V1, V2, V3. Thus, the power to this multivibrator is fed at the time when transistors V2, V3 are open. At this time, the resistance of their sections of the emitter - the collector is very small, and the emitters of transistors V4, V5 and V6 turn out to be practically connected with the plus output of the supply source. When transistors V2, V3 are closed, the multivibrator does not generate. In other words, the device on transistors V1, V2 and V3 plays the role of an automatic multivibrator power key on the transistors V4, V5, V6. A variable RP resistor serves to change the length of the pause. The LEDs VD1, VD2 are applied to the visual indication of the "pause" modes. In the repeat, you can use any low-power transistors, such as MP series p-N-P structures, CT 361, CT 203, CT3107, etc. The CT 816 transistor can be replaced by GT402, GT403, P201, P214, etc. As a power source, you can use solar panels, two batteries of type 3336 connected sequentially or from a power supply system with an output voltage 4.5 - 9 V. This device begins to work immediately and does not require additional settings.

Option number 3.
Underground rodent repeller can be collected on a very common chip K155LA3 Applying an intermittent signal generator scheme.

And to enhance the sound, use a two-stroke bat-transformer power amplifier as shown in Fig. 4.1A and 4.1b or using a sound transformer from low-power receivers as shown in Fig. 4.2 Power supply voltage - 4.5 - 5V. The principle of operation of an intermittent signal generator is similar to the device described in version 2. It also contains two generators, one of which forms the sound signal frequency you need, it is assembled on LE and non-DD1.3 DD1.4, the second manages the work of the first and assembled on LE and non DD1.1 DD1.2.

The frequency of each generator depends on the capacitance of the condenser and resistance of the resistor. For a generator on LE and - non-DD1.3 DD1.4 - C2, R2 and, accordingly, for the generator on LE and NOT DD1.1 DD1.2 - C1, R1. The frequency of the generated pulses is determined by the dependence F \u003d 1 / T; where T≈2.3cr, when compliance with the restrictive conditions for the selection of resistance of the resistor 240 ohms

Fig.4.1A.


And so fill on the details of the device in Fig. 4.1a. Chip K155L3 or K131L3, C1 - 2200 μF, C2 - 4.7 μF, C3 - 47 - 100 μF, R1-R2 - 430 Ohm, R3 - 1 com, V1 - KT315, V2 - KT361 or other low-power transistors, such as a series "MP". Dynamic head with a power of 0.25 W with a sound coil with a resistance of 8 - 10 ohms. To increase power, you can use transistors, for example V1 - GT404, V2 GT402. Power 4,5 - 5V

Fig.4.1b.


Option in Fig. 4.1b differs from the option in Fig. 4.1A A more powerful output audio amplifier assembled on three transistors. Details: Microcircuit K155L3 or K131L3, C1 - 2200 μF, C2 - 4.7 μF, C3 - 47 - 200 μF, R1-R2 - 430 Ohm, R3 - 1 com, R4 - 4.7 com, R5 - 220 ohms, V1 - KT361 (MP 26, MP 42, CT 203, etc.), V2 - GT404 (CT815, KT817), V3 - GT402 (CT814, KT816). Dynamic head with a power of 0.25 - 0.5 W with a sound coil with a resistance of 8 - 10 ohms. Power 4,5 - 5V

Fig. 4.2.


In the embodiment in Fig. 4.2 A TV-12 transformer is applied as the output amplifier (a transformer from any small-sized transistor receiver is applied). Dynamic head with a power of 0.25 W with a sound coil with a resistance of 8 - 10 ohms. Power 4,5 - 5V

Option number 4.
In the above schemes of the intermittent signal generators on the K155L3 microcircuit, the capacity of greater tank and resistors of small resistance include the reduced range of smooth adjustment of the frequency of control pulses. In repellers, the diagram of which is depicted in Fig. 5, a similar drawback is eliminated by turning on the transistor to the inputs of LE DD1.1, which plays the role of an emitter repeater with a large inlet and low output resistance. Therefore, it is possible to use resistors with greater resistance than in previous schemes, and the restrictive condition for selecting resistance looks like 240 ohms Fig. five

Details used: Microcircuit K155L3 or K131L3, C1 - 100 μF, C2 - 4.7 μF, R1 - 260 Ohms, R2 - 430 Ohm, R3 - 1 com, RP -30 com, V1 - KT361 (MP 26, MP 42, CT203, etc.), V2 - GT404 (CT815, KT817). Dynamic head with a power of 0.5 W with a sound coil with a resistance of 8 - 10 ohms. Power 4.5 - 5V.

Option number 5.
And one more device on a rather common foreign microcircuit from the 4000 series. This design is taken from the book "135 amateur devices at the microcircuit" by Newton S. Braga. (Project 25 Sound Alarm Device with Powerful Output (E, P) page 73)

Although the article refers to the alarm, but this device for scaring underground rodents is perfect for our topic. The design has a number of positive sides. Consider in detail the principle device operation. The output cascade on the transistors, they are able to give several hundred million hundred million into loudspeakers. As in the previous schemes, the device consists of an audio generator on LE DD1.2 and the control generator on LE DD1.1. The signal repetition frequency is adjusted by the RP1 resistor, the audiotone variable resistor RP2. Changing the tone and frequency of the pulse packets can be selected by the corresponding C1 and C2 capacitors. You can experiment, changing their values \u200b\u200bin accordance with the appointment of the device. The schematic diagram of the device is shown in Fig. 6.

Current consumed by a current - about 50 mA. Chip power supply 3-9 V. To improve acoustic characteristics The loudspeaker must be placed on a plastic surface or in a small case. CD 4093 microcircuit, domestic analog K561TL1.
Fig. 6.


Details used: RP1 - 1.5 MΩ, RP2 - 47 com, R1 - 100 com, R2 - 47 com, R3 - 4.7 com, C1 - 47 μF, C2 - 0.1 μF, C3 - 47 μF, C4 - 100 ICF. V1 - KT315 (KT815), V2 - KT361 (KT814), speaker 0.25-0.5 W- 4 - 8 ohms. Square batteries type 3336 are perfectly suitable for powering the device.

I wish you good luck, feel free to experiment, try. In the left column, options are proposed how to make described devices. And we will pride to the most malicious and bringing tangible damage - mice, rats, etc.

2. Rats, mice, horses, "pussy", chipmunks

These annoying "neighbors" cause damage not only in the garden, but also in everyday life, in warehouses, in basements, in the cellars, places of food storage, in the trums of ships, in the garages, spoil the wiring email. Nutrition, disseminate diseases much more. Think about - after all, on the purchase or manufacture of a scaring device, you will spend less means and efforts than constantly acquiring poisons, poisoned bait, capes, losing money.

Rodent discreteners are used not only in gardens and gardens, but also in various premises: household, warehouse, residential (apartments, offices, country houses, etc.), basements, in granaries, as well as in industrial and livestock enterprises.

What is the principle of work this device? What is his advantages over other methods? Rodent repeller emits ultrasonic waves (with a frequency exceeding 20 kHz), which, in turn, scare rodents.

Ultrasound frequencies extremely negatively affect rats and mice. The radiated sound waves cause them anxiety, fear, so rodents tend to leave the room irradiated with ultrasound. Rat repelters passed laboratory tests, as a result of which it was established that with a constant effect of the rat and mouse, the growing stressful state is experiencing, and within a few weeks leave the room. Usually, their care term ranges within two or four weeks, depending on the type of rodents, their number and on how much ultrasound radiation. Mice and beats for two weeks after the birth of the deaf, so the ultrasound does not work first on them. Recommended exposure time is four to six weeks. And as prophylaxis, the device can work constantly.

We will proceed to the description of the devices. I want to warn in advance that at high frequencies we need a more powerful signal strengthening than in devices for scaring underground rodents, this is associated with a feature of the passage of the high-frequency signal in the air and with the ability to play the signal with high-frequency dynamic heads. As a result, repellers consume a larger current, and feed them from the network aC voltage or OT car battery. The average current consumption of dischargers at the time of work is from 250 to 800 mA for EL meter. Energy similar consumption is practically not noticeable, but for batteries already significantly.

Option number 1
The proposed scheme in Fig. 7 you have already seen in devices for moles, the difference in the output cascade. To increase the output power, a composite transistor is applied here, and an alternating resistor is added in the signal generator. The speaker must be highly frequency with the resistance of the dynamic head of 8 ohms. Suitable, for example, from the TV - 2GD-36K, 8 ohms GOST9010-78, or from speakers. To increase stress in our small wards, in addition to changing the length of the pause resistor RP1, I added a variable resistance RP2 to change the signal frequency within 15 kHz. Such a combination strengthens stress in animals, and periodic change Sound frequencies forcing rats and mice will leave you faster.

The repeller radiates the beep from 28 kHz to 44 kHz. In the device, the pause attitude is 1/3. 5V supply voltage. The ratio in the choice of resistance is the same as in the devices described for underground rodents on the K155L3 chip3 microcircuit.

Fig.7.

IN concept In fig. 7 The following parts are used: Chip K155L3 or K131L3, C1 - 100 μF, C2 - 0.033 μF, R1 - 260 Ohms, R2 - 240 Ohm, R3 - 1 com, RP1 -30 com, RP2 -220 Ohm V1 - KT361 (MP 26 , MP 42, KT203, etc.), V3 - GT404 (CT815, KT817). Power 4.5 - 5V.

Option number 2.
At least at first glance, such a scheme seems difficult, I consider the most practical and universal. Like all previous options, with the correct assembly and the serviceability of the details begins to work immediately. The output power is 0.8 - 1W.

Fig.8.

How to make a radiator for underground rodents.
In different environments, the low-frequency sound wave applies to different speed And at different distance. As the emitter, we use the usual speaker from an old radio. To increase the efficiency of work and increase area distribution sound wave You can simply attach the speaker to a square or round plate of plastic. See their.

The loudspeaker diffuser when moving forward squeezes the air ahead and discharges from the garden. These areas of compression and discharge, enhance the diffuser, are superimposed on each other and mutually destroyed. When the diffuser movement, the same picture is obtained. Such an effect is called acoustic "short circuit": the diffuser only distinguishes the air on one side to another.

To resolve this effect, the loudspeaker is strengthened on the shield (screen). In this case, the change in the pressure in the air layer, directly adjacent to the diffuser, will be transmitted, and go further, i.e. There will be more powerful radiation of sound.

Place the collected emitter in dense polyethylene, so that the moisture does not fall and can bury in the right place, to the depth of 30-50cm

If you have any questions you can leave a message at: [Email Protected] I will share your experience with great pleasure.

Structurally, any color-chill (light-music) installation consists of three elements. Control block, power gain block and output optical device.

As an output optical device, it is possible to use garlands, it is possible to arrange it as a screen (classic option) or apply the electrical lamps of the directional action - spotlights, headlights.
That is, any means allowing you to create a certain set of colorful lighting effects.

Power amplification unit is an amplifier (amplifiers) on transistors with thyristor output controls. From the parameters of the elements used in it, the voltage and power of the light sources of the output optical device depends.

The control unit controls the intensity of light, and alternate colors. In complex special installations intended for the design of the scene during various types of shows - circus, theatrical and pop views, this unit is manually controlled.
Accordingly, the participation of at least one is required, and the maximum - groups of illuminator operators.

If the control unit is controlled directly to the music, it works for any given program, the color-chicing unit is considered automatic.
It is this kind of "colorwoman" usually collect novice designers with their own hands - radio amateurs, over the past 50 years.

The simplest (and popular) scheme of "colorwomen" on thyristors ku202n.

This is the most simple and perhaps the most popular color-chicted console scheme, on thyristors.
Thirty years ago, I first saw near a full-fledged, working "light summutor". She was collected by my classmate, with the help of an older brother. It was this scheme. Undoubted advantage is simplicity, with a sufficiently obvious separation of modes of operation of all three channels. Lamps do not blink at the same time, red canal low frequencies Sustainably blinks in rhythm with shock, medium - green responds in the range of human voice, high-frequency blue reacts to all the rest of the thin - ringing and fringing.

The lack of one is a preliminary power amplifier for 1-2 watts. My comrade accounted for almost "to the complete" cut off his "electronics" in order to achieve sufficiently stable operation of the device. As an input transformer, a lowering tr-p from a radio station was used. Instead, you can use any small-sized lowering network trance. For example, from 220 to 12 volts. Just connect it, you need to vice versa - low-voltage winding on the amplifier input. Resistors any, power from 0.5 watts. Condenters are also any, instead of thyristors KU202N, you can take CU202M.

Circuit "Currents" on CU202N thyristors, with active frequency filters and current amplifier.

The scheme is designed to work from linear audio output (the brightness of the lamp does not depend on the volume level).
Consider in more detail how it works.
The beep is fed from a linear output to the primary winding of the separation transformer. From the secondary winding of the transformer, the signal comes to active filters, through resistors R1, R2, R3 regulating its level.
Separate adjustment is necessary to configure the quality of the device, by aligning the brightness level, each of the three channels.

Using the filters, the signals are separated by frequency - to three channels. By first channel goes The lowest component of the signal - the filter cuts all frequencies above 800 Hz. The filter setting is performed using a R9 trimmed resistor. Capacitor rates C2 and C4 in the diagram are indicated - 1 μF, but as practice has shown - their capacity should be increased at least to 5 microf.

The second channel filter is configured to the middle frequency - from about 500, to 2000 Hz. The filter setting is performed using a R15 trim resistor. Capacitor rates C5 and C7 in the circuit are indicated - 0.015 μF, but their capacity should be increased, to 0.33 - 0.47 μF.

According to the third, the high-frequency channel passes all that above 1500 (up to 5000) Hz. The filter setting is performed using a R22 trim resistor. Capacitor rates C8 and C10 in the circuit are indicated - 1000 PF, but their capacity should be increased to 0.01 μF.

Further, each channel signals are separately detected (Germany transistors of the D9 series) are used), enhanced and fed to the terminal cascade.
The terminal cascade is performed on powerful transistors, or on thyristors. IN this caseThis is thyristors ku202n.

Next, it is an optical device, a design and an external of which depends on the fantasy of the constructor, and the filling (lamps, LEDs) is from the operating voltage and the maximum power of the output cascade.
In our case, these are incandescent bulbs 220V, 60W (if you set thyristors on the radiators - up to 10 pcs per channel).

The procedure for assembling the scheme.

On the details of the console.
CT315 transistors can be replaced by other silicon n-P-N transistors with a static gain of at least 50. Permanent resistors - MLT-0.5, variables and trimmed - SP-1, SPO-0.5. Capacitors - any type.
Transformer T1 with a 1: 1 coefficient, so you can use any with a suitable number of turns. With an independent manufacture, you can use the Magnetic Line of the C10X10, and the windings are coated with a wire PEV-1 0.1-0.15 to 150-300 turns each.

The diode bridge for the nutrition of thyristors (220V) is chosen based on the suspected load power, at least 2a. If the number of lamps per channel to increase - consumed the current consumed.
To power the transistors (12V), you can use any stable power supply unit for a working current to a minimum - 250 mA (and better - more).

First, each channel of the colorwoman is collected separately on the dumping board.
Moreover, the assembly starts from the output cascade. Having collected the output stage check its performance by applying a sufficient level on its input.
If this cascade is working normally, they collect an active filter. Next - check again the performance of what happened.
As a result, after testing, we have a real-working channel.

Similarly, it is necessary to collect and rebuild all three channels. Such a bore guarantees the unconditional performance of the device after the "finishing" assembly on the circuit board, if the work is carried out without errors and using the "tested" details.

Possible printing option (for textolite with one-sided foil). If you use a more overall capacitor in the lowest frequency channel, the distances between the holes and the conductors will have to be changed. The use of textolite with bilateral foils can be a more technological option - it will help to get rid of jumper hinged wires.

Use of any materials of this page, allowed if there is a link to the site

Each real radio amateur has a K155LA3 microcircuit. But they are usually considered strongly outdated and cannot find them serious use, as in many amateur radio sites and magazines, only flashes of flashes, toys are usually described. Within the framework of this article, we will try to expand the radio amateur outlook as part of the use of schemes using the K155L3 chip.

This scheme can be used to charge mobile phone From the cigarette lighter onboard network of the car.

Up to 23 volts can be supplied to the inlet of the amateur construction. Instead of an outdated transistor P213, you can use a more modern analog of KT814.

Instead of D9 diodes, you can apply D18, D10. SA1 and SA2 dumplings are used to test transistors with direct and inverse conductivity.

In order to exclude headlight overheating, you can set the time relay that will turn off the stop signals if they are burning over 40-60 seconds, the time can be changed by the selection of the condenser and the resistor. When you release and the next press pedal, the lanterns are turned on again, so that the safety of driving does not affect

To increase the efficiency of the voltage converter and prevent strong overheating, field transistors with low resistance are applied at the output cascade of the inverter.

The siren is used to supply a powerful and strong beep to attract the attention of people and effectively protects your left bike left for a short time.

If you are the owner of the garden, vineyard or a house in the village, then you know what tremendous damage can be created mice, rats and other rodents, and what costly ineffective, and sometimes dangerous is the fight against rodents standard methods

Almost all radio amateurs and structures are in their composition a stabilized power source. And if your scheme works from 5 volt supply voltage, then the best option There will be a three-way integral stabilizer 78L05

In addition to the chip in there is a bright LED and several components of the strapping. After assembly, the device begins to work immediately. Adjustment is not required, in addition to adjusting the duration of flashes.

Recall that the C1 condenser with a nominal 470 microfarads in the scheme strictly compliance with polarity.

Using the resistor rates of the resistor R1, you can change the length of the outbreak of the LED.

Siren is used to supply a powerful and strong beep to attract the attention of people and is used in fire alarm systems and automation, as well as in combination with signaling devices on various protected objects.

Generators in the scheme are marked with a yellow frame. The first G1 sets the frequency of changes in the tone, and the second G2 itself itself, which smoothly changes on the transistor VT1 included in series by passing R2. To select the desired sound, it is possible to use trimming resistors of the same values \u200b\u200binstead of resistances R1, R2.

When you turn on the supply voltage, the sound emitter begins to generate a tonal acoustic signal, the tone height varies with high to low and back. The signal sounds continuously, only the tone of the sound changes, which switches with a frequency of 3-4 Hz.

In the scheme of the siren, two multivibrators were used on the elements D1.1 and D1.2 K561LN2 chip, controlling the tone, and the multivibrator on the elements D1.3 and D1.4 of the same chip generating tonal signals. The pulse frequency generated by the first multivibrator on the elements D1.3 and D1.4 depends on the elements C2, R2 and C3, R4. Change the frequency of the pulse follows, and therefore the tone of the beep can be both resistances and tanks.

Suppose, at the initial moment at the multivibrator output on the elements D1.1 and D1.2 there is a level of a logical unit. Since the cathode of diodes VD1 and VD2 enters plus, then the diodes will be locked. Resistance R4 and R5, the operation of the circuit does not involve and the frequency at the multivibrator output is minimal, the low-alone signal sounds.

As soon as the output of these elements will establish logical zero diodes VD1 and VD2 will open and connect the resistance R4 and R5. As a result of the Nipped Multivibrator will increase.

The transistors used in the CT815 transistor scheme can be replaced by KT817, and KT814NA KT816. Diodes - KD521, KD522, KD503, KD102.

The following device can be used as an alarm or beep for a mountain bike. It is a two-dimensional siren and consists of a clock generator on DD1.1-DD1.3 elements, two tonal generators (first on elements DD2.1, DD2.2 and second on elements DD2.3, DD2.4), matching the cascade with Power amplifier on the DD1.4 element and the VT1 transistor.

The scheme consists of two generators. The first is used to generate a tone, the second to change and modulate.

For the maximum volume of volume, it is necessary that the frequency equivalent to its resonant frequency according to the bridge circuit.

The basis of the structure is a powerful multivibrator 4047, operating in unstable mode. All this is controlled by the powerful field MOSFET transistor VT1, which controls the NE555 timer, by generating the corresponding rectangular low frequency pulses, resulting in a fire siren. Switching operation modes continuously or intermittently is installed using a toggle.

The conclusions 10 and 11 of the microbrix 4047 give off the antiphase, the signals from which control the bridge on four MOSFET. To obtain the maximum volume, that is, the installation of the resonant frequency of the piezoelement, the confession resistance R6 is added to the design.

This scheme is composed of a combination of a musical synthesizer on the ISMS-8-08 microcircuit with a powerful output cascade of electronic siren. To start the scheme, a relay is applied, the winding of which has a galvanic junction from the rest of the scheme.

Microcircuit UMS has standard schema Connections. The three S1-S3 pushbutton switches make it possible to configure the chip to execute one of the melodies. When you click on the first button, the melody playback begins, and clicking on the third you can sort the melodies and select the desired one.

A selection of several scheme schemes on microcontrollers PIC

This scheme is a simple multi-skinned siren based on UM3561 micro

The diagram used speaker on 8 ohms, with a capacity of 0.5 W. With the help of two switches, selecting and playing different tones of the alarm sound. Each position generates its own sound effect.

The diagram below was collected in adolescence, in the class of a mug of radio engineering. And unsuccessfully. It is possible that the K155LA3 microcircuit is still not suitable for a similar metal detector, the frequency of 465 kHz is not the most suitable for such devices, and it may be necessary to shield the search coil as in the rest of the section "Metal detectors"

In general, the resulting "Pischaka" reacted not only to metals, but also on the arm and other non-metallic items. In addition, the microcircuits of the 155th series are too economical for portable devices.

Radio 1985 - 2 p. 61. Simple metal detector

Simple metal detector

Metal detector, the diagram of which is shown in the picture, can be collected in just a few minutes. It consists of two almost identical LC generators performed on the elements of DD1.1-DD1.4, the detector according to the doubling scheme of the straightened voltage on VD1 diodes. VD2 and high-resistant (2 com) BF1 headphones change the sound of the sound of which indicates the presence of an antenna metal object under the coil-antenna.

The generator collected on the elements DD1.1 and DD1.2 is excited by itself at the frequency of the resonance consistent oscillatory circuit L1C1, configured to a frequency of 465 kHz (used elements of the FIS filter of the superhometerodyne receiver). The frequency of the second generator (DD1.3, DD1.4) is determined by the inductance of the coil-antenna 12 (30 turns of the wire of the PEL 0.4 on the mandrel with a diameter of 200 mm) and the capacitor of the capacitor of the C2 container variable. allowing you to configure the metal detector to detect items of certain mass before searching. The beats resulting from the mixing of oscillations of both generators are detected by VD1, VD2 diodes. Filtered by C5 capacitor and arrive at BF1 headphones.

All device is collected on a small pCB, allowing meals from a flat battery for a pocket flashlight to make it very compact and easy to handle

Janeczek a Prosty Wykrywacz Melalia. - Radiolektromk, 1984, No. 9 p. 5.

Editorial note. When repetition, the metal detector can be used by the K155LA3 chip, any high-frequency German diodes from the Radio from the Radio "Alpinist".

The same scheme considered in more detail in the collection Adamenko M.V. "Metal detectors" M.2006 (download). Later article from this book

3.1 Simple metal detector on the K155LA3 microcircuit3

Beginner radio amateurs can be recommended to repeat the design of a simple metal detector, the basis for which was the scheme that has repeatedly published in the late 70s of the last century in various domestic and foreign specialized publications. This metal detector, made in just one K155L3 type chip, can be collected in a few minutes.

Schematic scheme

The proposed design is one of the numerous variants of the BFO type methodtectors (Beat Frequency Oscillator), that is, the device is based on the principle of analyzing the beats of two signals close in frequency (Fig. 3.1). At the same time, in this design, the assessment of the change in the frequency of the beats is carried out on the hearing.

The basis of the device is measuring and supporting generators, the oscillation detector of the HF, the indication circuit, and the supply voltage stabilizer.

In the design under consideration, two simple LC generators are used, made on the IC1 chip. The circuitry solutions of these generators are almost identical. In this case, the first generator, which is reference, is assembled on elements IC1.1 and IC1.2, and the second, measuring or rebuilt generator is made on IC1.3 and IC1.4 elements.

The circuit of the support generator is formed by the C1 capacitor with a capacity of 200 PF and the coil L1. In the measuring generator circuit, the C2 variable capacitor with a maximum capacity of about 300 PF, as well as the search coil L2 is used. At the same time, both generators are configured to the operating frequency of approximately 465 kHz.

Fig. 3.1.
Metal detector concept on K155L3 microcircuit

The outputs of the generators through the disconnecting capacitors of the SZ and C4 are connected to the detector of the oscillations of the HF, made on diodes D1 and D2 according to the doubling scheme of the straightened voltage. The load of the detector is the BF1 headphones on which the low-frequency component signal is released. In this case, the C5 capacitor shunt the load on top frequencies.

When the search coil L2 is approaching the oscillatory contour of the tunable generator to the metallic object, its inductance changes, which causes a change in the operating frequency of this generator. At the same time, if near the L2 coil is located from ferrous metal (ferromagnet), its inductance increases, which leads to a decrease in the frequency of the tunable generator. The color metal reduces the inductance of the coil L2, and the generator operating frequency increases.

The RF signal formed as a result of mixing the signals of the measuring and support generators after passing through C3 and C4 capacitors, is fed to the detector. At the same time, the amplitude of the RF signal varies with the frequency of the beats.

The low-frequency envelope of the RF signal is highlighted by the detector performed on diodes D1 and D2. The C5 capacitor provides filtering of the high-frequency component of the signal. Next, the beating signal enters the BF1 headphones.

Power on the IC1 microcircuit is supplied from the source B1 with a voltage 9 V through the voltage stabilizer formed by Stabilitron D3, the Ballast resistor R3 and the control transistor T1.

Details and design

To manufacture the metal detector under consideration, you can use any batch fee. Therefore, any restrictions associated with the details are not presented. overall dimensions. Installation can be both attached and printed.

When repeating a metal detector, you can use the K155LA3 chip, consisting of four logical elements 2I-non-not powered from the total DC source. As a C2 capacitor, you can use a condenser setting from a portable radio (for example, from the Radio "Alpinist"). D1 and D2 diodes can be replaced by any high-frequency German diodes.

The L1 coil contour of the support generator should have an inductance of about 500 μg. As such a coil, it is recommended to use, for example, a coil of the FIS filter of the superhometerodyne receiver.

The measuring coil L2 contains 30 turns of the wire of the PAL with a diameter of 0.4 mm and is made in the form of a torus with a diameter of 200 mm. It is easier to make this coil on a tough frame, but you can do without it. In this case, as a temporary framework, any suitable round item can be used, such as a jar. The coil's coils are wound up, after which they are removed from the frame and are shielded with an electrostatic screen, which is an unlocked aluminum foil tape, wound over the turn harness. The gap between the beginning and the end of the winding of the tape (the gap between the sections of the screen) should be at least 15 mm.

In the manufacture of the L2 coil, it is necessary to especially ensure that it does not happen - the closure of the ends of the shielding tape is, since in this case a short-circuit round is formed. In order to increase the mechanical strength, the coil can be soaked with epoxy glue.

For source sound signals High-resistant headphones should be applied with a large resistance (about 2000 ohms). Suitable, for example, the well-known Ta-4 or tone-2 phone.

As a power source of B1, you can use, for example, the Krone battery or two batteries of type 3336l, connected in series.

In the voltage stabilizer, the capacity of the electrolytic capacitor C6 can be from 20 to 50 μF, and the C7 condenser is from 3,300 to 68,000 PF. The voltage at the output of the stabilizer, equal to 5 V, is set by the R4 stroke resistor. Such voltage will be supported unchanged even with a significant discharge of batteries.

It should be noted that the K155LAZ chip is calculated on the power source with a voltage of 5 V. Therefore, if you wish from the circuit, you can exclude a voltage stabilizer unit and use one battery type 3336l or similar to it, which allows you to collect a compact design. However, the discharge of this battery will very quickly affect functional opportunities This metal detector. That is why the power supply is required, which ensures the formation of a stable voltage of 5 V.

It should be recognized that as a source of power, the author used four big round-based imported batteries connected in series. In this case, the voltage 5 in was formed by an integral stabilizer of type 7805.

The board with elements located on it and the power supply is placed in any suitable plastic or wooden case. A variable capacitor C2 is installed on the case cover, the switch S1, as well as the connectors for connecting the search coil L2 and the BF1 headphones (these connectors and switch S1 are not specified on the basis).

Salary

As with the adjustment of other metal detectors, this device should be configured under conditions where metal objects are removed from the search coil L2 to a distance of at least one meter.

First, using a frequency or oscilloscope, you must configure the operating frequencies of the reference and measuring generators. The frequency of the support generator is set to approximately 465 kHz by adjusting the core of the coil L1 and, if necessary, the selection of the capacitance of the C1 condenser. Before adjustment, it will be necessary to disconnect the corresponding condenser with C3 from the detector diodes and C4 condenser. Next, it is necessary to disconnect the corresponding condenser with C4 from the detector diodes and from the C3 capacitor and the C2 capacitor adjustment to set the frequency of the measuring generator so that its value differ from the frequency of the support generator is about 1 kHz. After restoring all connections, the metal detector is ready for operation.

Operating procedure

Holding search work With the help of the considered metal detector, it does not have any features. For practical use The instrument follows with a C2 capacitor with the necessary frequency of the beagi signals, which varies when the battery is discharged, change the ambient temperature or the deviation of the magnetic properties of the soil.

If during operation the signal frequency in the headphones will change, this indicates the presence of a non-metallic object in the area of \u200b\u200bthe search coil of L2. When approaching some metals, the frequency of the beagi will increase, and when approaching others, it is reduced. By changing the tone of the signal of the beats, having a certain experience can be easily determined from what metal, magnetic or non-magnetic, a detected subject is made.